1. Field of the Invention
The present invention relates to a method for recording information on an optical recording medium, and more particularly, to method and apparatus for recording information on an overwritable optical disk.
2. Description of Background Information
The recording density of an optical disk can be increased by reducing the diameter of the spot of a light beam to be irradiated on a recording surface. Reducing of the spot diameter of the light beam in consideration of downsizing an apparatus requires a small and high-power solid-state laser device which generates shortwave light. However, since such a laser device cannot easily be obtained, it is difficult to sufficiently raise the recording density of an optical disk.
If information is recorded on, for example, a magneto optical disk as an optical disk by modulating the magnetic field, simultaneous erasing of recorded information and recording of new information, so-called overwriting, is possible. For such an overwritable optical disk, by setting the data transfer rate at the time of data writing at a value higher than the rotational speed of the disk, the bit length of recording tracks formed on the recording surface of the disk can be made shorter than the spot diameter of a light beam, ensuring easy increase of the recording density along the beam's tracing direction irrespective of the diameter of the light beam spot. Even with the rotational speed of the disk and the data transfer rate controlled, however, it is still difficult to sufficiently increase the recording density of an overwritable optical disk because the recording density in the radial direction of the disk depends on the diameter of the light beam spot.